PCT International Search and Preliminary Examination Guidelines
15.43 The International Searching Authority carrying out the international search endeavors to discover as much of the relevant prior art as its facilities permit, and, in any case, consults the appropriate minimum documentation specified in Rule 34, and considers relevant databases or other search resources such as those listed in the Search Guidance Intellectual Property Digital Library (IPDL), which appears on the WIPO web site (www.wipo.int).
15.44 Thus, the International Searching Authority in searching an international application, in principle, consults all documents within the field of search that exists in the search files or databases, irrespective of their language or age, or of the type of document. Nevertheless, the examiner should, for reasons of economy, exercise appropriate judgment, based on his knowledge of the technology in question and of the documentation involved, to omit segments of the search file or databases in which the likelihood of finding any documents relevant to the international search is very small, for example, documents falling within a period preceding the time when the area of technology in question began to develop. Similarly the examiner need only consult one member of a patent family unless there is good reason to suppose that, in a particular case, there are relevant substantial differences in the content of different members of the same family or because only another member of a patent family was published before the international filing date and must therefore be cited in the first place.
15.45 The international search is carried out on the basis of the search files or databases which may contain material pertinent to the claimed invention. It covers all directly relevant technical fields within the PCT minimum documentation. The search may then have to be extended to include other listed resources or databases, such as those listed in the Search Guidance IPDL, or to analogous fields, but the need for this must be judged by the examiner in each individual case, taking into account the outcome of the search in the initial fields. See paragraph 15.61.
15.46 The question of which of the listed relevant search resources, including the databases listed in the Search Guidance IPDL, are to be consulted in a given area of technology must be judged by the examiner in each individual case. Classification places to be included in the international search should be selected in all directly relevant fields and, if necessary, in analogous fields. The examiner should consider all relevant search resources for the technology field and determine those most appropriate for the international application. Search resources listed in the Search Guidance IPDL relevant to the technical areas may provide a useful guide for relevance to the application at hand. This includes, for example, specialized search systems, abstracting journals, and on-line databases. Where searches are made by using the IPC, the selection of classification places in analogous fields should be limited to:
(i) higher subdivisions allowing searching by abstraction (generalization) inasmuch as this is justified from a technical viewpoint, and
(ii) parallel subdivisions, bearing in mind the fact that the fields in question will become increasingly unrelated.
15.47 Often various search strategies are possible that are relevant to the subject matter of the application. The examiner should exercise judgment based on experience and knowledge of the search resources, to select the search strategies most appropriate to the case in hand, and establish the order in which various strategies (that is, classification places, databases, and other resources) are to be consulted accordingly. This process should give precedence to the main technical field of the international application, and to the search resources and strategies in which the probability of finding relevant documents is highest.
15.48 The field of search should, where appropriate, include analogous fields to the extent they are consistent with the description and drawings.
15.49 The question of which arts are, in any given case, to be regarded as analogous is considered in the light of what appears to be the necessary function or use of the claimed invention and not only the specific functions expressly indicated in the international application.
(i) fields in which the same or similar structure would be expected by a person skilled in the art to be employed in different work or use;
(ii) fields to which a generic concept of claimed features pertains;
(iii) art within the field of the inventor’s endeavor and reasonably pertinent to the particular problem with which the inventor was involved;
(iv) fields relevant to the function or utility inherent in the subject matter covered by the claims, that is, the field to which the application is most likely to be applied would be searched in addition to the general field of the subject matter.
15.51 The decision to extend the international search to fields not mentioned in the international application must be left to the judgment of the examiner, who should not try to imagine all the kinds of applications of the claimed invention that might have been envisioned by the inventor. The overriding principle in determining the extension of the search in analogous fields should be whether it is possible that a reasonable objection that there is a lack of inventive step could be established on the basis of what is likely to be found by the search in these fields.